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Designing ferromagnetic Janus graphene nanoribbons via topological defect engineering

ORAL

Abstract

Symmetric zigzag-edged graphene nanoribbons (ZGNRs) (i.e., both edges are of the same zigzag structure) generally exhibit spin ordered edge-state magnetism that is ferromagnetically ordered along an edge but antiferromagnetically ordered across the edges. By eliminating or changing the magnetic properties on one edge, such modified ZGNRs can give rise to a new class of ferromagnetic or ferrimagnetic quantum spin chains, opening avenues for exploring quantum spin physics. In this work, we present a general strategy for designing ferromagnetic and ferrimagnetic GNRs in the form of Janus GNRs (JGNRs) with one edge different from the usual zigzag structure. Guided by Lieb's theorem and topological classification theory, we have engineered JGNRs with tailored magnetic properties by asymmetrically introducing a topological defect array of benzene motifs on one zigzag edge while preserving the integrity of the opposite edge. The predicted magnetic properties for such JGNRs were directly confirmed by numerical results from first-principles density functional theory as well as by scanning probe microscopy/spectroscopy measurements on two recently synthesized JGNRs, validating our general design principle [1].

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Publication: [1] Shaotang Song, Yu Teng, Weichen Tang, Zhen Xu, Yuanyuan He, Jiawei Ruan, Takahiro Kojima, Wenping Hu, Franz J Giessibl, Hiroshi Sakaguchi*, Steven G Louie*, Jiong Lu*, Janus graphene nanoribbons with localized states on a single zigzag edge (accepted by Nature)

Presenters

  • Weichen Tang

    University of California, Berkeley, Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory

Authors

  • Weichen Tang

    University of California, Berkeley, Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory

  • Steven G Louie

    University of California, Berkeley, University of California, Berkeley and Lawrence Berkeley National Lab, University of California, Berkeley and Lawrence Berkeley National Laboratory, Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Department of Physics, University of California at Berkeley, Berkeley, CA, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

  • Jiawei Ruan

    UC Berkeley, Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory